The possibilities of geometric 3-D inversion for processing the UAV-TDEM data

Summary The article is devoted to the assessment of the possibilities of using geometric 3D inversions of electromagnetic time domain data measured by induction receivers moved using UAVs (UAV-TDEM). The electromagnetic field is excited by a long grounded electrical line, and the survey is carried out over profiles parallel to it. The geometric 3D inversion proposed for use was developed for processing airborne electrical survey data using helicopter platforms and is based on a joint search for electrophysical and geometric parameters of a geoelectric model using block structures. The study of geometric 3D inversion workability is carried out on synthetic data generated for a geoelectric model containing local targets at different depths overlapped by inhomogeneous conductive layer. Modeling is carried out taking into account the characteristics of the UAV system, obtained on the basis of analysis of practical data measured in one of the areas of Eastern Siberia. The results obtained showed that, on the one hand, the considered UAV-TDEM technology with a source in the form of a grounded electrical line makes it possible to detect local objects at depths of up to 100 m (and, possible, more) even in conditions of a heterogeneous and sufficiently conductive overburden layers. On the other hand, the considered approach to geometric 3D inversion makes it possible to stably determine the position in plan and the depth of local objects for the UAV-TDEM technology.